The role of myocardial wall thickness in atrial arrhythmogenesis

Abstract

Changes in the structure and electrical behaviour of the left atrium are known to occur with conditions that predispose to atrial fibrillation (AF) and in response to prolonged periods of AF. We review the evidence that changes in myocardial thickness in the left atrium are an important part of this pathological remodelling process. Autopsy studies have demonstrated changes in the thickness of the atrial wall between patients with different clinical histories. Comparison of the reported tissue dimensions from pathological studies provides an indication of normal ranges for atrial wall thickness. Imaging studies, most commonly done using cardiac computed tomography, have demonstrated that these changes may be identified non-invasively. Experimental evidence using isolated tissue preparations, animal models of AF, and computer simulations proves that the three-dimensional tissue structure will be an important determinant of the electrical behaviour of atrial tissue. Accurately identifying the thickness of the atrial may have an important role in the non-invasive assessment of atrial structure. In combination with atrial tissue characterization, a comprehensive assessment of the atrial dimensions may allow prediction of atrial electrophysiological behaviour and in the future, guide radiofrequency delivery in regions based on their tissue thickness.

Segmentation Challenge on the Quantification of Left Atrial Wall Thickness

“…The posterior wall is found to be generally thicker than the anterior wall in the CT scans. This has also been reported in some meta studies [8]. Some algorithms have imposed a minimum thickness constraint, usually one pixel (i.e.…”

Cardiac CT assessment of tissue thickness at the ostium of the left atrial appendage predicts acute success of radiofrequency ablation

“…CCT is the optimal modality for assessing atrial wall thickness due to its high spatial resolution and clear identification of the endocardial surface. It is the most widely used modality for this indication, 5 but validation of CCT results against direct tissue measurements has been limited. Our study is the first to compare in vivo, CCTderived wall thickness measurements at specific atrial locations with human tissue measurements from a matched cadaveric cohort.…”

16th Atrial Fibrillation Symposium

“…In addition, many studies of RF lesion formation show that lesion depth is at least 3-4 mm, sometimes 4-6 mm at powers, contact force and durations typically employed for AF ablation. [41][42][43][44][45] The atrial wall may be 2-3 mm thick, and this must be taken into consideration.…”